Skin is subject to abuse by many extrinsic (environmental) factors as well as intrinsic (chronoaging) factors. A common extrinsic factor is exposure to ultraviolet radiation. Whether extrinsic or intrinsic, the abuse results in wrinkling of the skin. To many people, skin wrinkles are a reminder of the disappearance of youth. As a result, the elimination of wrinkles has become a booming business in youth-conscious societies. Treatments range from cosmetic creams and moisturizers to various forms of cosmetic surgery.
Chronoaging results in the thinning and general degradation of skin. As the skin naturally ages, there is a reduction in the cells and blood vessels that supply the skin. There is also a flattening of the dermal-epidermal junction which results in weaker mechanical resistance of this junction. As a consequence, older persons are more susceptive to blister formation in cases of mechanical trauma or disease processes. (See Oikarinen, (1990) "The Aging of Skin: Chronoaging Versus Photoaging", PHOTODERMATAL. PHOTOIMMUNOL. PHOTOMED. Vol. 7, pp. 3-4).
The tetrapeptide Arg-Ser-Arg-Lys, a preferred active of the present invention, is a basic fibroblast growth factor (hereinafter b-FGF) derived peptide corresponding to positions 107-110. European Patent Application 246 753, Baird and Ling, assigned to The Salk Institute for Biological Studies, published Nov. 25, 1987, discloses peptides derived from b-FGF, including the tetrapeptide Arg-Ser-Arg-Lys. The peptides are disclosed as being useful as FGF antagonists, which slow down or decrease cellular activity.
Baird, A., D. Schubert, N. Ling and R. Guillemin, (1988) "Receptor- and Heparin-binding Domains of Basic Fibroblast Growth Factor", PROCEDURES OF THE NATIONAL ACADEMY OF SCIENCES, Vol. 85, pp. 2324-2328, discloses b-FGF fragments whose amino acid sequences extend beyond positions 107-110 and act as potent antagonists in b-FGF present assays and as a slight agonist in b-FGF absent assays.
European Patent Application 339 905, Sheffield and Mezick, assigned to Ethicon Inc., published Nov. 2, 1989, discloses compositions comprising b-FGF or acidic FGF and a retinoid.